Phys Test 2 Flashcards
1
Q
Stimulating the enzyme adenylyl cyclase results in synthesis of the second messenger ________.
A
cAMP
2
Q
The cAMP activates ____________, leading to _________________ that either activates or inactivates target enzymes.
A
protein kinase A; phosphorylation
3
Q
What 2nd messenger mobilizes calcium from internal stores after being cleaved by phospholipase C?
A
Inositol triphosphate
4
Q
As calcium enter the cell the concentration increases as calcium is released from what structure?
A
Sarcoplasmic reticulum
5
Q
What will calcium bind to once it enters the cell?
A
Calmodulin
6
Q
What happens to the half life when hormones bind to plasma proteins?
A
Steroids: Longer half life
Protein: shorter half life
7
Q
What effect does a steroid hormone have on its target cells?
A
Increased protein synthesis
8
Q
What effect does a protein hormone have on its target cells?
A
Increased cell metabolism
9
Q
What is thought of as the “command center” of the endocrine system?
A
hypothalamus-pituitary complex
10
Q
What structure controls the pituitary gland by both neural and hormonal mechanisms?
A
Hypothalamus
11
Q
What pituitary is described below:
Epithelial component (glandular tissue)
Adenohypophysis
Vascular connection
A
Anterior Pituitary
12
Q
What pituitary is described below:
Neural structure (neural tissue)
Neurohypophysis
Neural connection
A
Posterior Pituitary
13
Q
Where are ADH and Oxytocin produced? Where are they stored?
A
Hypothalamus; Posterior pituitary:
14
Q
What nuclei controls the production and release of antidiuretic hormone (ADH) [vasopressin]?
A
Supraoptic nuclei (SON)
15
Q
What nuclei produce oxytocin?
A
Paraventricular nuclei (PVN)
16
Q
ADH and oxytocin are released into the capillary plexus of the __________________________ artery.
A
inferior hypophyseal artery
17
Q
What hormone stimulates contraction of smooth muscle of both the uterus during delivery and the breast to cause ejection of milk? (“Bonding Hormone”)
A
Oxytocin
18
Q
Stimulates kidneys to reabsorb water, decrease urine output, stimulates thirst center to increase fluid intake, and in high doses it causes vasoconstriction?
A
Antidiuretic Hormone (ADH)
19
Q
What cells within the hypothalamus produce hypophysiotropic (regulatory) hormones which control secretion of the anterior pituitary hormones?
A
Neuroendocrine cells
20
Q
What blood vessel delivers hypothalamic hormones directly to the anterior pituitary?
A
hypothalamic-hypophyseal portal blood vessels
21
Q
What will the hypothalamus secrete into the hypothalamic-hypophyseal portal blood vessels?
A
releasing hormones or inhibitory hormone
22
Q
The hypothalamic hormones can be delivered to the anterior pituitary ____________ and in __________ concentration
A
directly
high
23
Q
Cells from where receive high concentrations of the hypothalamic hormones?
A
anterior pituitary ONLY
24
Q
The hypothalamic hormones ___________ appear in the systemic circulation. (Do or Do not)
A
do NOT
25
What is Growth hormone's (GH) hypothalamic cell type?
Somatotrophs
26
What is Prolactin's (PRL) hypothalamic cell type?
Lactotrophs
27
What is Follicle-stimulating hormone (FSH) and Luteinizing hormone's (LH) hypothalamic cell type?
Gonadotrophs
28
What is Adrenocorticotropic hormone's (ACTH) hypothalamic cell type?
Corticotrophs
29
What is Thyroid-stimulating hormone's (TSH) hypothalamic cell type?
Thyrotrophs
30
Each of the anterior pituitary hormones is a ______________.
Peptide
31
What is synthesized and secreted by epithelial cells of the thyroid gland?
Thyroid hormone T3 and T4
32
What is the effect of thyroid hormone on the body?
Maintains metabolism
33
What is T3?
Triiodothyronine
| What is T3?
34
What is T4?
Tetraiodothyronine, or thyroxine
35
The thyroid gland is composed of a large number of ______________.
follicles.
36
Each follicle is surrounded by a single layer of epithelial cells (________________) and filled with a proteinaceous material called ____________.
(thyrocytes)
colloid
37
What is the primary constituent of colloid that is a large glycoprotein?
thyroglobulin
38
What is thyroid hormone secretions primarily regulated by?
thyroid-stimulating hormone
| (TSH) from the pituitary gland
39
What hormone will increase the secretion of TSH?
thyrotropin-releasing hormone(TRH)
40
What will inhibit the release of TSH?
Negative feedback fashion by circulating T3 and T4
41
TSH has a ______________ effect on the thyroid gland.
trophic
42
What leads to hypertrophy and hyperplasia of thyroid follicular cells and increased thyroidal blood flow?
sustained elevated levels of TSH
43
What inhibitory factor of TSH will inhibit the thyroid peroxidase enzyme?
Propylthiouracil(PTU)
44
What is Propylthiouracil(PTU) an effective treatment for?
Hyperthyroidism
45
Thyroid hormone contain a high amount of what element which must be adequately consumed through diet?
Iodide(Iodine)
46
hormone
| What will tyrosine residues of thyroglobulin found in the follicular lumen be iodinated to form?
Precursors of thyroid
47
When there is a dietary deficiency of Iodine, the ____________ ________________ increases its activity, attempting to compensate for the deficiency.
Na+-I− cotransport
| Iodide pump
48
What is the most important factor influencing the rate of iodide trapping by the thyroid?
Concentration of TSH
49
What enzyme will oxidize I- into I2?
thyroid peroxidase
50
Inside the lumen of the follicle, I2 combines with tyrosine of thyroglobulin to form?
monoiodotyrosine (MIT) and diiodotyrosine (DIT)
51
What will "salvage" I- and tyrosine after T3 and T4 have been delivered to systemic circulation?
Deiodinase enzymes
52
Thyroid hormones are __________ soluble, thus to circulate in blood, thyroid hormones must be associated with binding proteins.
lipid
53
What binding proteins will thyroid hormones use?
Thyroxine-binding globulin (TBG) ~ 70% “Resevoir”
Prealbumin (transthyretin) ~ 15%
Albumin~ 15%
54
Because of high affinity of the plasma-binding proteins for the T4 and T3, these substances are _________ released to the tissue cells.
slowly
55
T4(thyroxine) has a __________ latent period and a ____________ half life.
long
long
56
Structurally what hormone is thyroid hormone like? Characteristically what is it like?
Peptide hormone
steroid hormone
57
What enzyme converts T4(prohormone) into T3?
5'-iodinase
58
What are some main effects of thyroid hormone?
```
Increased BMR
- Increased body heat
- Increased O2 consumption
Bone formation
Increased glucose absorption
Increased cardiac output
```
59
Thyroid hormone induces the ___________________ of cardiac β1-adrenergic receptors which mediate the effects of the sympathetic nervous system to _______________ heart rate and contractility. (Sympathomimetic)
up- regulation
increase
60
What hormones does thyroid hormone work with to promote bone growth(formation) and ossification?
growth hormone and somatomedins
61
In the perinatal period, what hormone is essential for normal maturation of the CNS?
Thyroid horme
62
What are some physiological effects of thyroid hormone?
```
Increased thermogenesis and sweating
Increased rate and depth of respiration
Increased cardiac output
Increased pulse pressure
Increased utilization of substrates for energy
```
63
Elevated T3 & T4
| Decreased TSH
Hyperthyroidism
| What would have the following symptoms:
64
What would have the following symptoms:
Elevated T3 & T4
Decreased TSH
Hyperthyroidism
65
What disease is a type of hyperthyroidism?
Grave's disease
66
What would have the following symptoms:
Decreased T3 & T4
Elevated TSH
Hypothyroidism
67
In adults, what does thyroid hormone regulate?
metabolism
68
What are TSH secretions regulated by in the body?
Thyroid hormone levels in the blood
69
What symptoms
| would be noticed in a dietary deficiency of iodine intake(hypothyroidism)?
Cold intolerance
Low BMR
Obese
Decreased sweating and enlarged goiter at first
70
Where is growth hormone secreted from?
anterior pituitary gland
71
Growth hormone exerts its effects _________ on all or almost all tissues of the body not a specific target gland.
directly
72
What are the effect of Growth hormone?
Promotes linear bone growth
Hypertrophy of skeletal muscles
Promotes fat utilization for energy
Inhibits actions of insulin
73
What are the effects of growth hormone on metabolism?
Promotes the use of lipids
Enhances the uptake of AA and protein synthesis
Regulation of blood glucose(anti-insulin effect)
Increases gluconeogenesis in the liver
74
Growth hormone acts ___________ on liver cells to stimulate the production of Insulin-like growth factor 1 (IGF-1)
directly
75
Growth hormone has an indirect effect on childhood growth and anabolic effect in adulthood by using?
Insulin Growth Factor (IGF-1)
76
How does IGF-1 have a direct effect on anabolic factors?
Stimulates increase bone and cartilage growth (epiphyseal cartilage)
Stimulates muscle growth
77
In skeletal muscle, IGF-1 promotes the differentiation and proliferation of what type of progenitor cell?
myoblasts
78
Where is IGF-1 primarily produced?
Liver
79
What will growth hormone directly cause?
Lipolytic effect
Ketogenic effect
Increase lean body mass (regulating body composition)
80
What is the name of GH's ability to mobilize fatty acids from adipose tissue and then preferential utilize them for energy.
Lipolysis (lipolytic effect)
| - GH increases lipolysis
81
How does growth hormone cause a ketogenic effect?
GH impairs glucose uptake into adipose cells
| GH increases plasma levels of free fatty acids and ketoacids
82
What will occur as GH decreases the uptake and utilization of glucose by muscle and adipose tissue?
- Blood glucose concentration rise
| - Insulin secretion increases to compensate for the GH-induced insulin resistance.
83
GH increases glucose production through gluconeogenesis and glycogenolysis from the _________ and __________.
liver; kidney
84
How are growth hormone secretions regulated?
negative feedback loop
85
What feed back loop involves IGF -1 inhibiting secretions of growth hormone by the anterior pituitary.?
Long Loop Feedback System
86
What feed back loop involves GHRH inhibits its own secretion from the hypothalamus?
Ultrashort-loop feedback
87
What type of regulation is the ultrashort-loop feedback?
Autocrine regulation
88
What feed back loop involves effects of GH on hypothalamic GHRH and somatostatin secretion?
Short-Loop Feedback System
89
Hypothalamic neuropeptides (______________ ___ _____________) are released and carried to the pituitary gland via the hypothalamic-pituitary portal system
GHRH and somatostatin
90
What will stimulate the secretion of somatostatin from the hypothalamus? What will inhibit the release?
IGF-1 and GH
GH
91
What factors affect the release of GHRH from the hypothalamus?
Age
Time of day
Nutrient levels in the blood
Stress, and Exercise
92
At what point in development is there an enormous secretory burst, induced in females by estrogen and in males by testosterone?
Puberty
93
When is GH the highest? When does it steadily decrease?
puberty
Adulthood
94
In what stage of a normal sleep cycle are GH concentrations the highest?
early stages 3 and 4
95
GH is secreted in the body in what type of pattern(roughly every 2 hours)?
pulsatile pattern
96
The largest secretory burst occurs within __ ________ of falling asleep.
1 hour
97
What type of sleep will decrease the secretion of GH?
REM sleep
98
GH is classified as one of the "___________" hormones and is __________ by neurogenic and physical stress
stress; increased
99
Growth hormone is classified as what type of hormone?
Hyperglycemic
100
What will cause a reduced mean GH concentrations, associated with decreased pulsatile GH secretion and a shorter GH half-life?
obesity
101
What can obesity induce that will inhibit GH secretions?
Hyperinsulinemia
102
Excess growth hormone in childhood before the growth plates have closed can cause?
Gigantism
103
Excess growth hormone in adulthood after the growth plates have closed can cause?
acromegaly
104
What are some characteristics of acromegaly?
Prominent Jaw line
Enlarged Brow
Thickening of Bone
105
GH is produced best when insulin levels are _________.
low
106
What are some anabolic effects of growth hormone?
Increased glucose and amino acid uptake by skeletal muscles
Stimulation of protein synthesis
Increase in bone length and density
107
Where does the adrenal medulla originate from?
neuroectodermal
108
Chromaffin cells of the adrenal medulla primarily secrete what catecholamines?
epinephrine and norepinephrine
109
What does the adrenal medulla mainly secrete?
Epinephrine (80%)
110
The adrenal medulla secretes catecholamines in response to?
sympathetic neural input
111
What will catalyzes the conversion of norepinephrine to epinephrine?
PNMT- phenylethanolamine-N-methyltransferase
112
What are the physiological responses to fight or flight?
increased cardiac output and BP
Redistribution of blood flow
Increased ventilation
Decreased GI motility and secretions Increased blood glucose
113
What are the 3 layers of the adrenal cortex?
```
zona glomerulosa (outer region)
zona fasciculata
zona reticularis (inner region)
```
114
What does the zona glomerulosa secrete?
Mineralocorticoids (aldosterone)
115
What does aldosterone have important effect on?
Sodium and potassium balance
116
What does the zona fasciculata secrete?
Glucocorticoids (cortisol)
117
What will glucocorticoids influence?
carbohydrate, fat, and protein metabolism
118
What does the zona reticularis secrete?
Androgens
119
What weak androgens contribute to secondary sex characteristics?
DHEA and androstenedione
120
Collectively what are the hormones from the adrenal cortex referred to as?
Corticosteroids
121
What are corticosteroids synthesized from?
Cholesterol
122
The rate-limiting step in the synthesis of adrenocortical hormones is the side-chain cleavage of cholesterol to form _____________.
pregnenolone
123
The principal regulators of the adrenals are?
CRH
corticotropin releasing hormone
ACTH
adrenocorticotropic hormone
124
Where is ACTH produced?
corticotroph cells of the anterior pituitary gland
125
What is the activation sequence for the release of Aldosterone, Cortisol & Androgens?
Hypothalamus activates CRH ------> tell Ant. pituitary to make ACTH ---> send signal to adrenal cortex to make them
126
What single precursor is ACTH derived from?
pro-opiomelanocortin (POMC)
127
The synthesis and secretion of steroid hormones by the adrenal cortex depend on the stimulation of cholesterol ________________.
desmolase
128
Aldosterone will increase what in the kidneys?
Sodium Reabsorption & Potassium Secretion
129
What is the major stimuli(regulator) of aldosterone secretion?
Angiotensin II
130
Angiotensin II increases the synthesis and secretion of aldosterone by stimulating cholesterol desmolase and _____________ _________________.
aldosterone synthase
131
After synthesis what is aldosterone controlled by?
renin-angiotensin-aldosterone system. (RAAS)
132
What will be stimulated by a decrease in ECF volume causing a decrease in renal perfusion pressure?
Renin
133
What type of cells secrete renin?
juxtaglomerular cells of the kidney
134
Renin catalyzes the conversion of _________________ to angiotensin I
angiotensinogen
135
What will convert Angiotensin I to Angiotensin II?
ACE
136
How will aldosterone affect electrolyte transport in the colon?
increases sodium reabsorption from the colon and promotes potassium excretion in the feces.
137
How will aldosterone affect electrolyte transport in the sweat and salivary glands?
increases sodium reabsorption and promotes potassium excretion in sweat and salivary glands
138
Increase in plasma ______________ concentration increase aldosterone secretion, which in turn stimulates tubular secretion of potassium 🡪 _____ lost in the urine
potassium
K+
139
When is the highest secretory rates for cortisol noticed?
just before awakening in the morning
140
When is the lowest secretory rates for cortisol noticed?
during the evening hours and just after falling asleep
141
ACTH has a _________ and ____________ secretory pattern that drives a parallel pattern of cortisol secretion.
pulsatile
diurnal
142
What drives the diurnal pattern?
Your "internal clock" --> Hypthalamus
143
Overall, the effects of cortisol are __________ and Diabetogenic.
Catabolic
144
What is a catabolic example of cortisol?
Inhibition of inflammatory response
145
What does cortisol need in order to travel in the blood?
transport protein
146
What corticosteroid hormone will promote gluconeogenesis and storage of glycogen?
Glucocorticoids
147
How does cortisol promote gluconeogenesis?
- increases protein catabolism in muscle & decreases new protein synthesis
- increases lipolysis
- decreases glucose utilization by tissues
- decreases the insulin sensitivity of adipose tissue
148
What autoimmune disease has primary adrenocortical insufficiency?
Addison's disease
149
What zones of the adrenal cortex does Addison's diseases affect? What hormones are affect?
Destruction of all zones of the adrenal cortex
Decreased circulating levels of cortisol, aldosterone, and adrenal androgens
150
What physiological symptoms of Addison's disease?
Hypoglycemia
Anorexia, weight loss, nausea, vomiting
Weakness
Hypotension
Hyperkalemia
Metabolic acidosis
Decreased pubic and axillary hair in females
decreased libido
Hyperpigmentation (α-MSH fragment)
151
How will addison's disease affect ACTH levels?
Increased
| - negative feedback loop effect of low cortisol
152
What disease is an example of hypercortisolism (hyperglycemia)?
Cushing's syndrome
153
How does Cushing's syndrome affect ACTH?
ACTH levels are low
the high cortisol levels feed back on the anterior pituitary and inhibits ACTH secretion.
154
How does Cushing's disease affect ACTH?
primary defect is in the anterior pituitary, which is overproducing ACTH; ACTH levels are elevated
155
What can cause Cushing's syndrome?
chronic excess of glucocorticoids
| - tumor or meds
156
What are symptoms of Cushing's syndrome?
Hyperglycemia
Muscle wasting
Central obesity
Round face, supraclavicular fat, buffalo hump
Osteoporosis
Striae
Hypertension
Virilization and menstrual disorders in females
157
How does cortisol have an anti-inflammatory effect?
induces the synthesis of lipocortin, an inhibitor of the enzyme phospholipase A2 which produces prostaglandins and leukotrienes.
inhibits the production of interleukin-2 (IL-2) and the proliferation of T lymphocytes
inhibits the release of histamine and serotonin from mast cells and platelets
158
Cortisol up-regulates what type of receptors found on arterioles that will vasoconstrict in response to catecholamines?
α1-adrenergic receptors
- Important for maintenance of BP
159
How will low cortisol affect the blood pressure? High cortisol?
Hypotension
Hypertension
160
Where are glucocorticoids found in the brain?
limbic system
161
When is a largest bursts of ACTH and cortisol noticed?
just before waking
162
In males, adrenal androgens play only a __________ role.
minor
163
In females, the adrenal cortex is the _________ source of androgenic compounds.
major
164
In females, what are adrenal androgens are responsible for?
development of pubic, axillary hair, and libido
165
What "stress" hormone will elevate blood sugar and suppress inflammation?
Cortisol
166
What corticoid will suppress the immune system?
Glucocorticoids
167
How does your body get fast energy in the fight or flight response?
Breakdown of glycogen
Glucose released from liver
Free fatty acids released from adipose
168
What processes are inhibited or decreased in the fight or flight response?
```
Inhibition of processes associated with growth and repair
Inhibition of digestion
Inhibition of reproduction
Decrease in growth hormone
Decrease in sex hormones levels
```
169
What are the 3 stages of the general adaptive syndrome
Alarm
Resistance
Exhaustion
170
Chronic stress response is _________________ to long term survival.
MALADAPTIVE
171
What affects are seen with chronic stress?
Elevation of glucose & FFA
Increased cardiovascular function
Inhibition of growth and repair
Nervous system changes
172
Chronic glucocorticoid (GC) exposure in humans can result in whole-body ____________ _______________ and obesity.
insulin resistance
173
Metabolic syndrome is linked with _________ ________________, cardiovascular risk, and decreased survival.
insulin resistance
174
What 3 tissues are involved in calcium regulation?
Bone (and teeth), Intestine and Kidney
175
What 3 hormones are involved in calcium regulation?
PTH, calcitonin and activated vitamin D3
176
What is parathyroid hormones function? Where is it released from?
Parathyroid gland: raises calcium in blood
177
What is calcitonin's function? Where is it released from?
Thyroid gland: Lower calcium levels in blood
178
40 % of the calcium in the body is bound, what plasma protein is it mainly bound to?
Albumin
179
What form is unfilterable or not protein bound calcium in?
Free or ionized calciumm
180
Free, ionized Ca2+ is the only form of Ca2+ that is biologically ________.
active
181
Albumin has negatively charged sites, which can bind what ions?
H+ ions or Ca2+ ions
182
In acidemia, free ionized Ca2+ concentration _______________.
increases
183
In ____________, free ionized Ca2+ concentration decreases.
alkalemia
184
What structures inside the function in calcium balancing?
Kidneys - excrete Ca2+
GI tract - absorbs Ca2+
Bone does both
185
What hormone stimulates bone resorption (Increase in blood calcium)?
Parathyroid hormone
186
What vitamin stimulate bone absorption? What stops it from absorbing?
Vitamin D
Calcitonin
187
What type of cells within the parathyroid gland will secrete PTH?
Chief cells
188
How will PTH promote an increase in blood calcium levels?
Promotes the release of calcium from bone tissue
Stimulates kidneys to conserve calcium
* PTH acts direct and is mediated by cAMP;
189
What type of bone cell has receptors for PTH?
Osteoblasts
190
How does PTH act on the intestines (GI)?
PTH acts indirectly stimulating intestinal Ca2+ absorption , via activation of vitamin D
191
PTH secretion is regulated by the ________ ___________.
plasma [Ca2+]
192
What are PTH's 2 actions on the kidneys?
inhibits phosphate reabsorption
- Inhibiting Na+-phosphate cotransport in the PCT of the nephron
stimulates Ca2+ reabsorption
193
What is the name for the phosphaturic action of PTH that causes the phosphate that was resorbed from bone to be excreted in the urine?
Phosphaturia
194
What will inhibition of Na+-phosphate cotransport cause?
Decreased phosphate reabsorption and phosphaturia
195
What is the flow of Vitamin D through the body?
Skin --> Liver --> Kidney
196
In the liver, what is vitamin D converted into?
25-hydroxycholecalciferol
197
*rxn stimulated and tightly controlled by PTH
| In the cortex of the kidney's, what enzyme will convert 25-hydroxycholecalciferol into 1,25-dihydroxycholecalciferol?
1 alpha hydroxlase
198
What is the physiologically active form of vitamin D?
1,25-dihydroxycholecalciferol
199
What will stimulate 1 alpha hydroxlase?
Increase in PTH
Decrease in free [Ca++]
Decrease in [calcium binding protein
calcium-stimulated ATPase
alkaline phosphatasePhosphate]
200
Vitamin D stimulates formation of what in the intestines?
calcium binding protein
calcium-stimulated ATPase
alkaline phosphatase
201
What is the overall role of vitamin D?
increase plasma levels of both Ca2+ and phosphate & to promote mineralization of new bone
202
What is secreted from the parafollicular cells (C cells) found in the thyroid gland?
CalcitoIn
203
What will stimulate the secretion of calcitonin?
in response to elevation of the extracellular calcium concentration
Calcitonin "tones down" [Ca++]nin
204
How does calcitonin differ from PTH?
calcitonin does not participate in the minute-to-minute regulation of the plasma [Ca2+]
205
What would cause increased calcitonin levels? Decreased levels?
Thyroid tumors
Thyroidectomy
206
What does the pineal gland release in the absence of light?
Melatonin
207
What is the function of melatonin in the body?
Regulation of circadian (or biological) rhythm
Promotion of sleep
?- Regulation of certain reproductive hormones (LH/FSH)
208
What will stop the release of melatonin?
light exposure
209
When are melatonin levels high or low?
Low during daylight hours
| Higher during dark periods
210
What is a photoperiod?
the length of day versus night
211
What can melatonin block in smaller mammals?
Gonadotropins (LH and FSH)
212
ex) when melatonin is low, gonadotropins are high
What type of relationship does melatonin and gonadotropins(sex hormones) have in humans?
The are Inversely related
213
When are melatonin levels the lowest? Highest?
morning
evening
214
What is the brains master bio clock that receives light and dark cues from the retina through the optic nerve to update the circadian rhythm?
superchiasmatic nucleus of the hypothalamus
215
How does melatonin production shift throughout the year?
Summer: shorter daily periods
Winter: longer periods
